JP2608459B2 - Waste liquid treatment method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for treating waste liquid, and more particularly, to a method for efficiently treating a very harmful waste liquid using a specific microorganism. It is about.

(Prior Art) Conventionally, as a sewage treatment method, a mechanical method, a chemical method such as coagulation sedimentation, and a biological method using activated sludge or microorganisms are known ("Chemical Dictionary 2", Kyoritsu Shuppan (Showa
42-9-10) p149).

However, waste liquids containing cyanide, copper, etc. are extremely toxic to activated sludge and various microorganisms.
It cannot be processed by the biological methods currently used frequently. Other methods are inefficient and unsuitable for industrial mass processing.

(Problems to be Solved by the Invention) As described above, at present, no industrial method for effectively treating highly toxic waste liquid has been developed.

Among the highly toxic waste liquids, the waste liquids containing cyan and copper are particularly frequently generated from chemical plating plants. However, plating plants are often located in urban areas and there are many small factories, making it impossible to build large-scale wastewater treatment facilities. of cyanide (CN ^-) runaway accident or copper ions do not cut off the mark.

Nevertheless, if there is a large-scale treatment facility, it may be possible to purify wastewater by repeating the process even if it is mechanical or physical, but technology cannot be achieved with a small facility. Is the current situation.

(Means for Solving the Problems) The present invention has been made in view of the current state of the art, and has been made in order to solve the above problems at once.

Therefore, as a result of examination from various fields, it was recognized that a system using a powerful biological method is particularly advantageous as a system suitable for processing in a small-scale facility.

However, in the activated sludge method, cyanide and copper become poisons for sludge, and the intended purpose cannot be achieved. The method of using microorganisms is the same, but he pointed out that there may be bacteria that can detoxify cyanogen and copper among microorganisms that exist indefinitely.

Therefore, the present inventor has screened a wide range of microorganisms useful as sewage treatment bacteria and deodorizing bacteria from a vast number of microorganisms, and can use them as sewage treatment bacteria to greatly reduce scum. Moreover, not only is it excellent in deodorizing effect, but also decisively, it has succeeded in isolating from the soil a strain that can not only harm cyanide and copper but also positively detoxify them.

One strain isolated here was identified as belonging to Bacillus subtilis in mycological properties, but not only has excellent usefulness such as scum reduction and deodorization, but also detoxifies cyanide and copper. It also has a completely new utility of, and these outstanding novel properties are not found in conventional strains of Bacillus subtilis, so this isolate was recognized as a new strain of Bacillus subtilis, Was named Bacillus subtilis kubota.

This strain is Bacillus subtilis Kubota FERM P-9463.
Has been deposited with the National Institute of Advanced Industrial Science.

Next, the bacteriological properties of Bacillus subtilis kubota are described.

(A) Morphology 1. Cell shape and size Short bacillus, 1.2-1.4 × 3.6-3.8 μm 2. Cell polymorphism There is no particular. Involved in the cell membrane and has a nucleus. In addition, it has spores and is characteristic, and Septum can be observed.

3. Existence of motility There is motility, about 10 flagella.

4. Spore presence Spores are present.

5. Gram staining Gram positive. Stained blue with Faber G Set (Nissui).

6. Acid-resistant stains red with teal and Nelsen stains. It is an acid-fast bacterium.

(B) Growth state in each medium Inoculate a broth agar plate in a state of being suspended in physiological saline, culture at 37 ° C. for 24 hours, and grow well.

This shows an R-type in which the periphery of the settlement does not become circular. The color is opaque, pale yellow.

Sheep blood agar culture, heart-in fusion agar culture,
It shows R-type, opaque, and pale yellow color on tryptosome agar culture, and all have good growth. The growth state in each medium is as follows.

The new isolate Bacillus subtilis kubota used in the present invention grows well on any nutrient medium. In particular, chicken manure extract, animal manure extract, etc. are excellent extracts.

The culture is performed at 20 to 40 ° C, preferably at about 30 to 38 ° C, for 10 to 24
Proliferates well even when left open for hours.

The resulting culture contains a large amount of cells,
It can be added to sewage treatment plants and septic tanks as it is to effectively remove CN and Cu.

In addition, the culture can be separated from cells by centrifugation, washed well, and mixed with a bulking agent such as starch or talc to obtain a microbial preparation.

The Bacillus subtilis kubota of the present invention survives well in all dosage forms and, when used, has an excellent effect on water, air and soil purification.

The cells and / or cultures thereof according to the present invention may be used as they are for the treatment of wastewater, or may be used for wastewater treatment, such as by adhering and coagulating on the surface of commonly used carriers such as activated carbon and glass beads. Can be advantageously used for wastewater treatment according to the conventional method. The detailed mechanism of wastewater treatment by this bacterium must be studied in the future.However, in the case of cyanide, the fungus decomposes into carbon and nitrogen by the action of the bacterium, and in the case of copper, the bacterium takes it into the cells. Once estimated,
If the cells are sedimented and removed, the copper is rendered harmless.

After removing the cyan and copper ions in this manner, it may be discharged as it is, or if necessary, may be further treated according to a conventional method of wastewater treatment such as activated sludge treatment, sedimentation treatment, coagulation treatment. It is possible.

In a mouse oral administration test using only the cells of Bacillus subtilis kubota of the present invention, the LD ₅₀ was almost infinite, and there was no change in the mouse skin application test.

 Next, culture examples and examples of the present invention will be described.

Culture example Starch 10 g Meat extract 3 g Peptone 10 g Sodium chloride 5 g Water 1000 ml (pH 7.0) A medium having a composition of not less than 500 ml is placed in a 500 ml flask, and Bacillus subtilis kubota FERM P-9463 is inoculated into the flask, and 37 ° C.
For 20 hours.

The obtained culture was centrifuged to separate the cells, and the cells were mixed with 300 g of starch to prepare a microbial preparation.

Cyan solution Example NaCN was dissolved in water (CN ^- 50 ppm as)
And 100 ml of a copper solution (10 ppm as copper) in which CuCN was dissolved in water, respectively.

On the other hand, in the above-mentioned culture example, the cells were separated, added to the waste solution at a rate of 5 g / each, then placed in a thermostat, and allowed to stand for 1 day, 3 days, and 5 days later. The amount of each residue was measured. Ventilation was performed by blowing air into the beaker once a day.

In addition, the treatment was performed for 5 days in the same manner as described above, except that aeration culture was performed by constantly blowing air.

 Then, the results shown in the following table were obtained for each processing.

As is clear from the above results, it is understood that both of cyan and copper can be almost completely removed after 5 days by treating according to the present invention. In particular, with respect to cyan, a remarkable effect that 90% or more is rendered harmless by only one day of treatment is obtained.

Further, if the ventilation process is continued, the effect will be further enhanced, and for cyan, the concentration will be drastically reduced from 50 ppm to 0.23 ppm, and for copper,
It was clearly seen that the removal and detoxification were completely completed from 10 ppm to 0 ppm, demonstrating the outstanding remarkability of the effect of the present invention.

(Effect of the Invention) As described above, according to the present invention, the use of a conventionally unknown new strain allows the cells to be killed by copper and cyanide wastewater, which are highly biotoxic, but rather completely kills the cells. Are, on the contrary, successful in detoxifying them.

Moreover, since the efficiency is extremely high, the processing efficiency is extremely high, a large amount of waste liquid can be processed in a short time, and the intended purpose can be sufficiently achieved in a small-scale processing facility.

Therefore, the present invention can be used not only in large-scale processing in a large factory or a local public organization, but also very advantageously in a small-scale plating factory.

Claims (1)

(57) [Claims] (1) A waste liquid containing cyan and / or copper is treated with Bacillus
A method for treating a waste liquid containing cyan and / or copper, which is treated with Bacillus subtilis Kubota.